Hold on to shares of Vodafone once the sale of its stake in Verizon is completed, the Sunday Telegraph's Questor column said. Vodafone will pay 104p a share to shareholders from the proceeds of the sale. After that, Vodafone is a potential takeover target for AT&T and other North American buyers. The shares are a solid hold because the mobile phone operator will be flush with cash after the deal with options to make acquisitions and spend on new technology. After the Verizon deal completes, Vodafone will trade at about 25 times earnings - high for a low growth company but things could change quickly.Get out of shares in Rockhopper Exploration, the Sunday Times's Danny Fortson said. Rockhopper shares rose last week after Premier Oil repeated its commitment to exploring in the Falkland Islands, where Premier sold a controlling stake in its reservoir two years ago, promising to fund development. But Rockhopper's boss Simon Lockett is leaving with no successor in place. His replacement will face extreme pressure from shareholders for a change in strategy so Lockett's pledge may be worthless. In his Inside the City column Fortson said Rockhopper should be very worried and if he was an investor he would sell. Buy shares of TyraTech, whose Vamousse treatment kills head lice and their eggs without pesticides the Mail on Sunday's Midas column said. Walmart, the biggest US retailer, will start stocking Vamousse, which is made from plant and vegetable oils, in April. The global head lice market is worth more than £430m a year and TyraTech should gain market share because lice have become resistant to many existing treatments. The company has also developed repellents for animals and humans - a market worth almost £1.5bn a year. Its bosses are experienced and adventurous investors should reap rewards.Darty shares are ones to hold on to, Questor advised in the Sunday Telegraph. The company, formerly known as Kesa Electricals, is listed in London but focuses on selling electrical goods in France. It reported like-for-like sales up 3.2% last week but its French gross margin narrowed sharply. The shares trade on 21 times forecast earnings and are not cheap but an expected recovery in profits will reduce that multiple to 17 times.Please note: Digital Look provides a round-up of news, tips and information that is impacting share prices and the market. Digital Look cannot take any responsibility for information provided by third parties. This is for your general information only as not intended to be relied upon by users in making an investment decision or any other decision. Please obtain a copy of the relevant publication and carry out your own research before considering acting on any of this information.